\documentclass{article}
\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}H(0) = D = P_1//
H(1) = A+B+C+D = P_4//
H'(0) = C = P_2-P_1//
H'(1) = 3A+2B+C = P_4-P_3\end{equation*}
\end{document}
